A controller of an injection molding machine controls mold clamping of a fixed mold and a movable mold. The controller includes a servomotor drive control unit for limiting increase in driving current during driving of a mold clamping servomotor, and a moving state acquisition unit that acquires a detection signal of an encoder. The controller further includes an abnormality determination processing unit for determining that a clamping force sensor is abnormal when recognizing stoppage of movement of the movable mold during mold clamping, based on the acquired detection signal of the encoder.

An injection molding machine, and a method of controlling the injection molding machine, can prevent a molding defect. The injection molding machine can mold a product for each execution of a molding cycle through an injecting process of injecting a material into clamped molds, a dwell process of controlling dwell pressure of the material in the molds, and a cooling process of cooling the material in the molds, the injection molding machine including a mold opening amount sensor and a controlling unit, the mold opening amount sensor being configured to detect a mold opening amount of the molds, the controlling unit being configured to control clamping force of the molds and the dwell pressure based on the mold opening amount during the molding cycle.

An injection mold for molding a flip-top closure having a body portion and a lid attached to the body portion by a living hinge has first and second mold portions for defining first and second portions of the flip-top closure respectively, a lid closing tool for closing the lid of the flip-top closure on the body portion after a molding of the flip-top closure in the injection mold and before an ejection of the flip-top closure from the injection mold, and first and second linear actuators operatively connected to the lid closing tool for moving the lid closing tool about first and second axes respectively. The first and second linear actuators are controllable to move the lid closing tool along a lid closing path for closing the lid. An in-mold lid closing device and a method for making a flip-top closure are also disclosed.

A mold clamping apparatus according to the present invention includes: a fixed platen to which one mold of a pair of molds is to be mounted; a movable platen which is disposed opposite the fixed platen and to which the other mold is to be mounted; a pressure-receiving platen connected to the fixed platen via tie bars; a mold opening/closing mechanism including a toggle link mechanism for opening/closing and clamping the molds by moving the movable platen back and forth; a drive mechanism including a servo motor for driving the mold opening/closing mechanism; and a control device for controlling the servo motor, wherein the control device includes an acceleration/deceleration adjustment section capable of adjusting an acceleration time, a deceleration time and a target speed of the servo motor during a mold clamping operation.

An injection molding machine including a mold clamping device for clamping a mold comprising a fixed mold and a movable mold by a predetermined mold clamping force; an injection device for injecting and filling a resin into the mold by a predetermined injection pressure, wherein the mold clamping device enables natural compression of the resin at least as the resin inside the mold solidifies; and a molding machine controller at least including a specific molding condition setting function for setting a specific molding condition by obtaining a parting opening amount which becomes a predetermined gap between the movable mold and the fixed mold during injection filling, a molding injection pressure which becomes an injection pressure capable of molding a good product and a molding clamping force which becomes a mold clamping force capable of molding a good product; a fast injection condition setting function for setting, as a fast injection condition, a fast injection speed from the start of injection, the fast injection speed being higher than the injection speed set by the specific molding condition, and a fast injection section for continuing the fast injection speed; and a molding control function for mold-clamping the mold clamping device by the molding clamping force, setting the molding injection pressure to a limit pressure, injecting and filling the mold by the fast injection condition from the start of injection, and filling the mold by the specific molding condition by the end of the fast injection section.

A molding injection pressure Pi with which a parting opening Lm is formed between a movable mold 2m and a fixed mold 2c during injection-filling and which allows formation of a good molded article is obtained and set in advance. A molding clamping force Pc that allows formation of a good molded article is obtained and set in advance. During production, a mold clamping device Mc is clamped with the molding clamping force Pc, and an injection device Mi to apply the molding injection pressure Pi as a limit pressure Ps is driven to injection-fill a mold 2 with resin R. A parting opening detector 3 that detects the parting opening Lm is provided. During production, reset control is executed to reset the parting opening detector 3 to zero if reset timing tr set in advance has come at least on condition that given preparation for injection is completed after clamping. The reset timing is set in a range covering a given period Zs before injection start time and the given period Zs after the injection start time.

An injection molding method of a resin molded article closes a first die and a second die by a predetermined clamping force, conducts pressure holding and cooling after filling a cavity formed between the first die and the second die with a molten resin, and opens the first die and the second die. The injection molding method conducts clamping, filling, pressure holding, and cooling for the first die and the second die by a clamping force previously specified on the basis of a sample with which pressure in the cavity during a cooling process indicates a minimum and which is specified from samples of clamping forces.

A distortion sensor is provided on each of a plurality of tie bars and the extension amount of each tie bar is detected by the distortion sensor thereof, whereby a mold clamping force actually applied to a mold is measured. This measurement specifies the part of the mold that first opens and obtains a minimum mold clamping force that does not open the mold in that part. The minimum mold clamping force thus obtained is the minimum mold clamping force that does not open the mold without being influenced by factors such as the shape and the arrangement of a cavity in the mold and the mold clamping force balance of a mold clamping part of an injection molding machine.

In an injection molding system, an amount of deformation of an elastic member is calculated from image data of the elastic member causing a nozzle to generate a nozzle touch force and a nozzle touch force of the nozzle is calculated by converting the amount of deformation. Accordingly, it becomes possible to detect abnormal conditions such as resin leakage and mold deformation and exercise correct control of the nozzle touch force.

In an injection molding system, a holding force changing means reduces a holding force to a predetermined level or less if a predetermined or higher load is detected by an external load detection means after a molded article is transported to a work area of an operator by a molded article transport device. Thus, the operator can easily take out and inspect the molded article.